Engineer-facing detail
Technical notes for M&E and energy teams.
If you're designing, specifying, or signing off voltage optimisation on a UK commercial or public-sector site, this is the page to read. Covers harmonics, VSD compatibility, install requirements, M&V methodology, warranty, and standards.
Power quality and harmonics
Volta VO units add no measurable total harmonic distortion (THD). We test to EN 61000-3 for emissions and to BS EN 50160 for supply characteristics at the output. If your site has existing harmonic concerns, typically six-pulse VSDs or large IT loads, VO will not exacerbate them; the unit is passive in the harmonic sense.
Voltage stability at the output is regulated within a narrow band against incoming voltage variation. Sag and swell events on the incoming supply pass through, which is the correct behaviour. The unit is not a voltage conditioner or active regulator, and it shouldn't be specified as one.
VSDs, BMS, and downstream controls
VO sits upstream of your distribution, which means any downstream control system (VSDs, soft starters, BMS, drive controllers, lighting controls) continues to operate on the voltage envelope it was designed for. There is no integration required, no commissioning on the controls side, and no ongoing coordination.
For sites running VSDs on major motor loads: the VSD input sees a reduced, stabilised voltage, which typically improves drive-input power quality and modestly extends drive capacitor life. VSD output to the motor is unchanged. Drive control programmes run as designed.
If you run a BMS with metering on the main incomer, you'll see a step reduction in consumption post-install. We'll coordinate with the BMS provider if you want the pre/post data captured automatically; most of our M&V reports lean on the incomer meter directly.
Compatibility with backup, UPS, and generation
UPS-backed loads are unaffected. UPS supplies their own regulated voltage from battery during a mains event, and their mains input is upstream of the VO unit in most topologies. The UPS sees the same mains envelope it was specified for, bypass operation unchanged.
Back-up generators connect via a changeover panel that bypasses the VO unit. During generator operation, the site runs on generator voltage (typically 400 V). VO operates only on mains supply.
On-site solar PV and CHP are compatible. The configuration depends on where the generation ties into the site distribution. We confirm the exact topology during survey. Generation tied in downstream of the VO unit continues to operate at the reduced site voltage; generation tied in upstream continues to operate at full grid voltage.
Installation requirements
- Physical space for a floor-standing or wall-mount enclosure sized to your incoming capacity (we confirm footprint at survey).
- Access to the incoming supply for the install, typically between the billing meter and the main distribution board.
- A planned supply outage of 2–4 hours for most single-incomer sites; extended windows for multi-transformer or critical sites.
- Authority to work on the incoming supply (we hold appropriate DNO liaison and install under our insurance).
- No ongoing power, cooling, or consumable requirements once commissioned.
Measurement & Verification methodology
Our default M&V approach is a pre/post comparison at the same incoming meter, reconciled over matched operating periods:
- Baseline. Minimum 3 months of pre-install consumption data from the billing meter or HHD operator, extended to 6 or 12 months for sites with strong seasonal variance.
- Install and commissioning. Clean break point with commissioning certificate dated.
- Post-install measurement. Matched 3 / 6 / 12 month window, reconciled against weather (heating-degree-days) where heating or cooling is a major load, and against production volume for manufacturing sites.
- Reconciliation. Measured kWh difference expressed as a percentage of baseline consumption, with assumptions listed.
- Report. Written in a format that reads sensibly for finance, estates, and sustainability audiences. Can be submitted as supporting evidence for SECR, ESOS, and Greener NHS / PSDS reporting.
For sites with existing IPMVP-compliant M&V regimes, we'll align with your chosen option (typically Option C for whole-facility, sometimes Option B for a sub-circuit where the VO unit sits on a specific feed). We're comfortable in either framing.
Warranty and service
Standard unit warranty covers manufacturing defect and in-service failure for several years from commissioning; extended cover is available. Exact warranty terms are issued with the proposal and confirmed on commissioning. They depend on unit capacity, enclosure type, and site operating conditions.
Units have no consumable parts and do not require routine servicing. We recommend an annual visual inspection as part of your normal electrical intermediate inspection, and we'll come out under warranty if anything outside expected behaviour is observed.
Standards and certifications
- EN 61000-3, electromagnetic compatibility (emissions)
- BS 7671, UK wiring regulations
- BS EN 50160, voltage characteristics at the supply
- CE marked, UK manufactured
Company-level accreditations (ISO, NICEIC, Constructionline, etc.) are confirmed during procurement. Ask us to include the specific accreditation set you need evidence of with the proposal.
Common questions from M&E teams
Will VO affect our DNO agreement or G99 documentation?
No. VO is a passive in-line device and doesn't change your relationship with the DNO. It's not a G99-relevant device in its own right (it doesn't export to the grid). If you have an existing G99 certificate for on-site generation, that remains unchanged.
What happens if the VO unit fails?
Units are specified with an internal bypass that brings the site back onto unoptimised mains supply if an internal fault is detected. The fault is logged and we come out under warranty to diagnose and repair. In all the sites we've installed, a unit failure looks like "we pay our unoptimised bill again until Volta's engineer arrives", not "the site goes dark".
Can we use our own installer?
Yes, on commercial agreement. We supply the unit, the install spec, the commissioning procedure, and the warranty terms. Your installer works to our spec; we sign off the commissioning remotely and warrant the unit as normal. This is common on sites where an existing framework installer has to do the physical work.
Does VO interact with ripple-control or half-hourly signal circuits?
Ripple-control signals pass through unaffected. They use frequencies well outside the mains envelope VO operates on. Half-hourly signal for metering is a billing-circuit concern upstream of the VO unit and is unchanged by install.
Is there a minimum site size below which VO doesn't make sense?
Commercially, yes. We typically look for annual electricity spend above about £50,000 before the capex clears most internal payback thresholds. Technically, the physics works at any site size; it's the capex-vs-saving that dictates the floor. For smaller sites, bundling as part of a multi-site portfolio or a landlord-common-area install can make the numbers work.
How do you handle sites with existing PV inverters and export meters?
We position the VO unit downstream of the grid incomer and upstream of the site distribution. PV that imports to the site (downstream of VO) sees the reduced site voltage. PV that exports to the grid (upstream of VO, or via its own export meter) sees full grid voltage. The configuration is confirmed during survey; we've installed on sites with both topologies.
Want a datasheet or a technical call?
We'll send full product documentation under NDA if that's easier than starting with a survey. Happy to talk to your M&E team directly.